I installed R 3.2.2 on my Laptop(Mac Air), and the original language was Chinese.
I use system("defaults write org.R-project.R force.LANG en_US.UTF-8") to change language to English.   
Then, the language on my R app(GUI) has changed. But in terminal R, the language still remain Chinese.     
I use language = EN, the language could change.    
After shutting down the terminal, the R on terminal still remain Chinese.   
Were there someone met similar problem?
 
     
    